


In Over His Head

by Dietcokediamond



Series: Following Orders [2]
Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Best Friends, Established Relationship, Explicit Sexual Content, F/F, F/M, Fluff and Smut, Friendship/Love, Married Sex, Multi, Nipple Licking, Nipple Play, Oral Sex, Plot What Plot/Porn Without Plot, Porn With Plot, Porn with Feelings, Scissoring, Setleth Week (Fire Emblem), Smut, Threesome - F/F/M, Vaginal Fingering, Vaginal Sex, that one time byleth was poly af
Language: English
Status: Completed
Published: 2020-07-13
Updated: 2020-07-16
Packaged: 2021-03-05 02:34:15
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 8,991
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25246954
Author URL: https://archiveofourown.org/users/Dietcokediamond/pseuds/Dietcokediamond
Summary: "Every explicit drawing or sinful novel he’d ever seen, every depraved imagining that had plagued him before he confessed his love to Byleth – they were nothing compared to watching her now, consumed with desire for another woman."---A fluffy, smutty threesome fic (with ~feelings~) for Setleth week. The story of Seteth and his beloved wife, the woman who loves her most, a secret, and a naughty book...
Relationships: Dorothea Arnault/My Unit | Byleth, My Unit | Byleth & Seteth, My Unit | Byleth/Seteth
Series: Following Orders [2]
Series URL: https://archiveofourown.org/series/1829074
Comments: 4
Kudos: 39





	1. Chapter 1

**Author's Note:**

> If you're here to cut straight to the sex, read this one and then go to Chapter 3. Otherwise, I really hope you enjoy, and that I did this thrupple justice. Setleth is the OTP obviously, Dorothea and Byleth close second so I mean??? It ain't rocket science.

**Summary for the Chapter:**

> Seteth sees something he wasn't meant to see. Byleth helps him... come to terms with it.

The night was eerily silent, save for the quiet, echoing footfalls of Seteth’s boots against the cobblestone as he made his way from his office to the quarters he secretly shared with Byleth. Although working for hours on end and burning the midnight oil were customary to Seteth, he had promised his dear wife that he would make a conscious effort to arrive home to her before she fell asleep - which proved difficult at times, seeing as he had spent centuries in the habit of working tirelessly through the night.

Hesitant though he was to abandon the day’s work earlier than he might have liked, spending time with Byleth was an absolute necessity. After the countless years he’d spent in solitude, to love another person so completely was exhausting – and brilliant. So much so that his heart began to ache were they ever apart for too long. He yearned for the time they could announce their marriage to the public, but until then, the stolen moments he spent wrapped in her arms in their chambers were enough. Even now, the thought of her waiting for him made his heart flutter, and he quickened his steps.

Opening the door as gently as possible, so as not to make too much noise just in case Byleth _had_ fallen asleep, Seteth let himself in and locked the door behind him – and froze at the unfamiliar sound of another woman’s laughter.

Damn. It was Tuesday, meaning Byleth was hosting her weekly ladies’ book club with some of her students. She had mentioned it to him many times before, and he quite enjoyed watching her face light up as she regaled him with the rousing discussions she had shared with her clubmates, but it was very much unlike them to still be meeting at this hour…

Peeking into the foyer, Seteth confirmed his suspicions. Byleth and Dorothea were splayed comfortably on the couch, each of them holding a mostly empty glass of wine (a decidedly empty bottle had been discarded several feet away). They were obviously invested in their conversation, giggling through their words; apparently, the club meeting had been over for a while, and the two of them were simply catching up now.

Seteth felt his shoulders droop a bit, disheartened that he wouldn’t have Byleth all to himself tonight. But, after all, she needed time with her friends as well, and the two of them were clearly enjoying themselves. Perhaps he would simply leave them to it, return to his office, and make it up to her in the morning...

The two of them burst into laughter at some sultrily murmured joke from Dorothea, Byleth laughing mid-sip and managing to spill a burgandy circle of wine around her lips. Guffawing, Dorothea licked her thumb and brought it to Byleth's face, wiping the wine away. Their eyes met -- and in an instant, something changed. Their laughter died down breathily, leaving a tense silence as the two of them stared at one another, their cheeks flushing prettily, frozen in place.

Seteth’s breath caught in his throat, and he felt his heart skip a beat. He had seen this look on many young faces throughout the years – a quiet spark of lust, followed by an unsure realization that the other feels it too. Then, a growing tension; a deep anticipation as to who will move first…

Seteth felt his own face burning as a bewildering mixture of emotions overtook him; shame that he was watching his wife without her knowledge, a twinge of jealousy—and, at the very core of him, a shiver of arousal.

Their lips met. Slowly. Nervously.

Seteth’s blush deepened, forcing himself to look away—then finding himself unable to do so.

Dorothea’s hand crept up to caress Byleth’s face, but she lost her nerve at the last moment and pulled away. “My goodness, look at me,” Dorothea gave a nervous laugh, turning her face from Byleth. “I’m such a mess. Forgive me, Professor…”

Byleth stared at her, her face as mysterious as ever, and waited for her to continue.

“This is embarrassing, coming from me of all people,” Dorothea took a sip of her wine to bolster herself, “but I think the wine reminded me of some foolish feelings I used to have for you, back before the war.” She was grinning, making light of herself with a humor that didn’t reach her eyes. “I really was quite the cliché; a naïve student, pining after her wise and worldly teacher.” A trill of laughter escaped her lips. “Isn’t that silly?”

Byleth didn’t join in Dorothea’s laughter, but instead found herself pulling towards her to tuck a silken strand of hair behind her ear. The ghost of a smile tugged at the corners of her lips. “I don’t think it’s silly at all.”

The women paused, locked in each other’s gaze. Seteth felt his heart beating in his ears. “Your teacher would have been lucky to have you,” Byleth concluded. Then, she brought herself to a slightly wobbly stand, breaking the stifling connection between them. Seteth released a breath he hadn’t realized he’d been holding. “Speaking of which, you have to read this novel I’ve come across lately—”

Seteth, startled into action by Byleth’s movement, opened the door as silently as possible and squeezed himself outside, moving as quickly as he dared without making too much noise.

 _Goddess, what had just happened?_ What was he to make of all this? Dorothea had kissed his wife – and she hadn’t pulled away. A jumbled stream of conflicting thoughts raced through his mind as he shuffled towards his office.

Was Dorothea in love with Byleth? It wouldn’t really matter, of course, because Byleth loved him, and he knew that without doubt. But there was _something_ there, between the two of them just now. He had seen it; he had _felt_ it. _What must their lips have felt like, pressing up against each other_ … stop it, you lecherous old fool, peeping on your wife like a filthy rogue— _oh, Goddess, the tender way they had touched their flushed cheeks…_

Arriving at his office door once again, Seteth hurriedly scrambled for his keys and let himself back in, eager to forget himself in a few more hours of his work. Everything would be fine, he was overreacting. He knew this.

He knew this, so there was no need to think of it further. None at all.

~*~*~

Several hours later, with the welcomed comfort of total exhaustion enveloping him, Seteth slipped back into their quarters, stripping himself of his robes as he went, eager for the nothingness of a deep sleep. Byleth was asleep, of course - it had to be only a few hours until sunrise – and the outline of her sleeping figure called to him like the song of a siren.

Wasting no more time, Seteth climbed into bed and wrapped himself around Byleth, his limbs fitting perfectly around her slight body as he felt his entire body relax. He was asleep in seconds.

All too soon, Seteth emerged from the fog of sleep, sunlight bombarding him as he felt Byleth pull away.

“Another late night, it seems,” Byleth said tersely, stretching her stiff muscles as she forced herself awake. “I was hoping to have a nightcap with you…”

“I’m sorry, my love,” Seteth struggled to find his voice as he rubbed his tired eyes. “There were some, ah, unexpected issues concerning the monastery’s… kitchen budget.”

Byleth raised an eyebrow. “Kitchen budget?” she repeated with a bemused smirk.

“Yes,” he said, clearing his throat and sitting up. “Nothing you need to concern yourself with, darling. I am sorry I was out so late.” He took her hand and softly pulled her towards him, the smell of her surrounding him as he pressed a kiss to her neck.

“Well,” Byleth hummed, tangling her hands in his hair. “I’m prepared to forgive you, if you can find a way to make it up to me.”

Seteth smiled against her skin and gave a small chuckle. “I’m sure I can think of something.”

“Well, you certainly missed an interesting evening,” Byleth said, the flirtatious lilt never leaving her tone. “Dorothea kissed me last night.”

Seteth’s eyes widened, heat spreading across his cheeks in a way that Byleth loved; she _so_ enjoyed flustering her husband like this.

“I… er, I…” Seteth shrunk beneath Byleth’s playful gaze. Keeping up his façade any longer was pointless, he knew – and he had no desire to hide things from her anyway. “…I know. I came in and saw the two of you.” Byleth raised her brow. “I-I didn’t mean to!” Seteth insisted, holding her tighter. “That’s why I was out late, I just… didn’t want to interrupt.”

“I’m shocked that the late-night kitchen budget meeting turned out be a farce,” Byleth teased, and Seteth gave a relieved smile. “I just thought you should know,” she continued, “since _I_ would be upset if someone touched _your_ mouth without asking me.”

Seteth, feeling his heart throb with affection, pressed an earnest kiss against Byleth’s cheek. “Thank you for telling me, my love. I must admit, I… I wasn’t sure what to think.”

Byleth closed the remaining distance between them, pulling herself up onto Seteth’s lap. “Really? What first came to your mind?”

Seteth groaned at her closeness, feeling a tightness stirring deep in his gut as his body reacted. “At first, I was jealous…”

“Hmmm,” Byleth curved her tailbone just a bit, pressing the apex of her thighs flush against Seteth’s bare stomach. “Jealous of what?”

“That she was kissing you like that,” Seteth enunciated through gritted teeth, his cock stiffening further as she pressed her heat against him, only the thin layer of their smallclothes separating them now. “The way… you looked at each other…”

“And _after_ the jealousy?” Byleth prodded, bringing her fingers up to tease the point of Seteth’s ear, causing him to shudder. His hands grasped the sides of her waist, anchoring himself. Seteth captured her lips with his hungrily, certain that she could feel how desperate he was for her – he hoped that was a sufficient answer.

It was not.

Byleth pulled herself away, forcing their lips apart. “Answer me.”

Seteth groaned again, bucking his hips. “Seeing you kiss her like that, it made me—” He hissed as she brought her hand down to the bulge in his trousers. “ _Agh_ , it made me want you so much,” he spat out, his voice clouded in shame, head reeling with need. He grabbed the plump skin of her ass and squeezed. “Like this.”

Now it was Byleth’s turn to kiss him, her tongue wrestling for dominance as she ground herself against his throbbing erection. “Just like this?” she repeated, relishing the effect she was having on him. “You know you have nothing to worry about Seteth,” she simpered, pulling away just enough to slide her hand beneath his pants and wrap her fingers around his girth. “You know I’m _yours_ , whenever you want me…”

With that, Seteth pushed her down into the bed with one swift motion, finding himself poised between her legs as he kissed her furiously. “ _Now_ ,” he huffed, parting their lips just long enough to pull his braies down and toss them away. She followed suit. “I want you now.”

He kissed her fervently, his fingers drifting through her silky folds with ease until he found the _exact_ right spot – Byleth keened, wriggling beneath him impatiently.

Seteth was usually a very generous lover, taking his time to kiss and tease every inch of Byleth’s skin until she saw stars, his fingers and tongue knowing exactly where to go. But there was no time for that now – the two of them were aching to be joined, having already spent far too long apart, and neither could deny themselves any longer.

He slid himself into her with ease, clenching his fist into the sheets beneath her as he regained control of himself. “Goddess, you feel incredible,” he sighed, beginning to thrust into her, and watching her breasts bounce tantalizingly as he did.

He felt a sharp pressure building inside of him already, urged on by the obscene noises Byleth made with his every move. Contrary to her typical demeanor, Byleth was insatiably loud in bed, a trait that Seteth found absolutely maddening.

With every thrust, her voice grew louder, her moans higher, until she was barely holding on. “ _F-Faster…_ ” she choked out, her breath catching in her throat as her face twisted in pleasure. Seteth did as he was told, almost to the brink himself.

“Hah –I –I can’t…” he groaned, holding her hips firmly in place as he fucked her, “…m-much longer—”

Just then, he felt Byleth contract around him, her voice breaking in a shrill cry as she took her pleasure around his length. Seteth felt his eyes roll to the back of his head as he came as well, spilling himself inside of her over and over as she milked him dry. _“Byleth!”_ he cried out, much louder than he intended.

He felt as though his soul left his body as his movements slowed to a halt, pulling out of her and falling in an exhausted heap at her side.

“Consider yourself forgiven,” Byleth panted, slinging a heavy arm over him and planting a kiss on his nose.


	2. Chapter 2

**Summary for the Chapter:**

> One week later - a discovered secret, a dirty novel, and an intriguing offer...

A week had come and gone without much excitement, and frankly, that was just the way Seteth liked it. After so many years of fearing for Flayn’s safety, of running Garreg Mach to the very best of his ability and coming to truly love its students, and reuniting all of Fodlan -- this long-awaited peacetime had Seteth practically giddy at the idea of filling out mindless paperwork.

So, he had spent the day scratching away at endless parchment, allowing his mind to wander freely as his practiced hands took over for him. He even found himself plotting out ideas for fables; it had been so long since he’d written something…

The uneventful day went by rather pleasantly, and Seteth now found himself preparing to lock up for the evening and head home to his wife. It was still rather late, all things considered – most students had likely been asleep for at least an hour – but in Seteth’s mind, he was throwing caution to the wind and leaving early.

Outside their door, Seteth surveyed the cavernous hallways around him; silence. Not a soul. Satisfied, he quietly let himself in.

Finally, he was crossing the threshold of their chambers, already untying the knots of his belts. “Hello, Darling,” he called, spotting his wife on the couch. “How was your book club?”

Byleth lets out a happy cry as she stands to greet him, plucks a bottle of wine from the shelf, and pours some for him. “It took you long enough!” She ignored his question, her voice jovial and a bit tipsy. Seteth beamed at her.

“Forgive me, my love,” he said, discarding his robes with a soft groan, happy to be free of their bindings. Byleth looked him up and down with a grin, rather brazenly, and he chuckled as he felt himself blush a bit. “But it seems you’ve been able to amuse yourself in my absence, at least.”

Byleth pouted, wrapping her arms around her husband’s shirtless form and giving him a squeeze; he melted into her embrace with a contented hum. “You haven’t kissed me yet,” she scolded. “Some advisor you are.”

Seteth laughed and pressed his lips against hers, eager to make up for his oversight. He nearly jumped out of his skin when Dorothea rounded the corner, emerging from the privy.

“A-Ah! I-I-…..” Seteth felt his entire body flush in panicky shame, gooseflesh spreading over his back and arms. _By the Goddess, what was she doing here?_ His presence in Byleth’s room would be hard enough to explain on its own, but with him being partially undressed—

“Oh yeah,” Byleth snapped, as though remembering an exciting bit of trivia. “Dorothea’s here.”

“Er, B-Byleth,” Seteth choked out, then immediately corrected himself. “ _Archbishop_ , I’m terribly sorry for intruding, I…” He was floundering desperately, his eyes frantically scanning the room for his discarded robe. “I had a pressing liturgical matter to ask you about, but perhaps tomorrow we-”

Dorothea raised an eyebrow at him and let out a raucous, squeaking laugh. “Oh, come off it, Seteth,” she scoffed. “You honestly thought that would work?”

Byleth joined in Dorothea’s laughter. Seteth’s gaze fell to the floor, but he slowly gave a begrudged smile. “I… I suppose not,” he admitted. He crossed his arms against his chest warily, all too aware of its bareness.

“I must say, I’m rather cross that you thought I wouldn’t notice,” Dorothea teased, coming up next to Byleth and nudging her with her hip. “The two of you are always together, after all, but it’s more than just that. The little _looks_ across the room, the way your eyes light up when you see each other – honestly, it’s the sort of stuff they write operas about.”

She met Seteth’s gaze now, her face filled with genuine affection for her professors. “And the way you look at her!” she added, exasperated. “It’s enough to make all the other ladies of Garreg Mach jealous.”

Seteth was touched at her words. It was no secret, amongst those closest to them, that the two of them were at the very least smitten with each other, but discretion was absolutely vital – especially while the unity of Fodlan was still in its infancy. If word were to get out, the people would fear corruption.

Byleth smiled at him now, her eyes brimming with affection through her tipsy fog, and Seteth felt his heart skip a beat. “We haven’t told anyone, but we were married soon after we defeated those who slither in the dark.” She wrapped her arms around him again, delighting in showing her affections openly. “It is sometimes difficult to keep up professional appearances.”

“We hope we can rely on your discretion,” Seteth added warily, though one look at Dorothea’s kind smile assured him he need not say it. Dorothea was Byleth’s closest friend – not just her student, but her peer – and she would not betray her trust.

“Of course,” Dorothea waved him off, and reunited with her own glass of wine on the desk. “You are a very lucky man, Seteth,” she said, raising her glass in a toast before finishing the last of it.

“Well! It has certainly gotten late. And I’m sure there are _other things_ the two of you would like to be doing,” she teased, flashing Byleth a mischievous look. Byleth giggled. Seteth cleared his throat.

“Oh, but before I go, Professor! I wanted to tell you, I finished reading that book you lent me. It was every bit as… _awe-inspiring_ as you said!”

Byleth guffawed, which sent Dorothea into a fit of laughter as well. Clearly, Seteth had missed the joke.

“What book is that?” he asked, crossing the room to grab the untouched glass of wine Byleth had poured him. Alcohol had very little effect on him, but he quite enjoyed the flavor of wine; and besides, the girls were clearly enjoying themselves. He should try to as well.

“Oh, I very much doubt you’ve heard of it,” Dorothea purred, and the two of them burst into laughter again.

“What did you think about the scene in the mountain cave…?” Byleth grinned, a tint of pink spreading across her face.

“I’ll never look at a wyvern tail the same way again!”

Seteth’s raised his brow at the mention of wyverns, genuinely interested if not a bit wary of their suspicious laughter. “It’s a book about wyverns?”

“It’s the story of a demoness who falls in love with a human mercenary hired to kill her,” Byleth explains. “But she saves his life, dooming him to be her slave. She ends up using her tail -- like a long wyvern tail -- to bind his hands…”

Seteth’s eyes widened slowly, realization dawning on him.

“Yeah,” Dorothea adds, “then she rips his pants off!”

“Where did you find such a book?” Seteth gasped. “Not here in the monastery, surely!”

“There are only a few copies in the library,” said Byleth. “All the girls are taking turns reading it.”

“ _What?_ What is the title, I have to inspect it immediately!” Seteth demanded, his voice a little louder than he intended.

“Awww, calm down,” Byleth shushed him. Dorothea was trying her damnedest not to laugh at the two of them. “It’s all in good fun.”

“But we can’t allow the _students_ to see it!” Seteth insisted, getting rather worked up.

“And why not?” Byleth countered, enjoying his reaction. “What would happen if they saw it?”

“It would… _give them ideas_!” Seteth hissed. He had enough trouble with the hormone-ridden young men ogling their classmates as it was; the last thing he needed was the young ladies peddling smut.

“Well, _you’ve_ had to read them to rule out the naughty ones,” Dorothea added with a teasing lilt, joining forces with Byleth. “Do they give _you_ ideas?”

Seteth felt a flush of heat rush to his cheeks, much to their delight. “Nonsense, I assure you I am unaffected by them,” he insisted tersely.

“Unaffected!” Dorothea repeated gleefully, her cheeks beginning to ache.

Byleth’s eyes drifted away for a moment, as if she were searching for a memory just out of reach. “Remember when I used the _ice spell_ on my mouth? You said you got _that_ idea from a book...”

Seteth’s jaw dropped. “B-Byleth!” he gasped, scandalized.

With that, the two women cackled, toppling over each other sloppily and dropping onto the couch as their laughter overtook them. Seeing the two of them so full of joy, even at his expense, warmed Seteth’s heart – and he even allowed himself to chuckle as well. Perhaps he should let his guard down a bit – after all, they were only teasing him.

Their laughter was persistent, even more giddy at the awkward way they landed on top of each other in a tipsy mess. They locked eyes for a moment, delighted by their shared clumsiness.

And suddenly, there it was again -- A bolt of lightning between them, their smiles fading as they gaze at one another with understanding. Seteth felt the hair on his neck stand up on end, his heart pounding as the room grew silent.

Byleth’s head was swimming, the sweet smell of Dorothea’s hair flooding her senses. She couldn’t help but stare at Dorothea’s cleavage, which was now only inches away from her face. _Oh, Sothis, she was so beautiful.._.

Seteth feels as though he is made of stone, completely unable to move, to breathe, to _think_. He can feel the heat emanating from them, their mutual attraction locking them in place, and he can do nothing but watch. Another deluge of mixed emotions came over him – shame, desire, possessiveness.

He could feel Byleth’s eyes on him, and followed her gaze to his hips. He was half-erect, a small but noticeable mound protruding from his breeches. He adjusted himself as subtly as possible, but it made no difference – Dorothea had already caught on.

Byleth, never taking her eyes off Seteth, reaches out a tentative hand and places it on Dorothea’s breast, Dorothea’s breath hitching in response.

Seteth felt his length twitch at the sight. His hand betrays him, and before he can readjust, he freezes in midair, utterly caught. Dorothea’s mouth broadens into a cheeky grin, which only proves to make his cock harder.

_Byleth… Byleth’s hand… It was…_

Dorothea releases a held breath, causing her breast to stir a bit in Byleth’s palm. _Goddess help me…_

“I must say, it’s intriguing to see this side you two,” she said under long eyelashes, an amorous look that was at once shy and coy - almost predatory. Byleth was enchanted by it.

Dorothea’s eyes turned to him. “Especially you, Seteth. I never realized you had such a toned body beneath those robes,” she winked.

Seteth swallowed, his mouth incredibly dry, and said nothing.

“If only Sylvain could see you now,” Byleth simpered, looking over her husband’s shirtless form hungrily.

“Sylvain?” Dorothea repeated, laughter tumbling out of her like ringing bells.

“Seteth hates Sylvain,” Byleth explained.

“I do not _hate_ him,” Seteth insisted, his voice returning to its usual confident, authoritative tenor that Dorothea was used to. “His behavior towards you is simply inappropriate for a learning environment, and can’t be tolerated by-”

“He flirts with _everyone_ , Seteth,” Byleth chided, but the twinge of a smile on her face gave her away; she was touched by her husband’s jealousy.

He raised his brow defensively, eyes widening. “But he flirts with _you_ whenever I’m around! On _purpose!_ ” he spat back, his voice jumping two octaves, and Dorothea had to cover her face to hide her grin.

Seteth was usually so stoic and unwavering – to see him so uncharacteristically vocal, so vulnerable and expressive, was completely foreign to Dorothea. Her heart swelled as she watched the two of them together, bickering as though she weren’t even there, and came to the realization that it was the Professor’s love that had allowed for this; that even over-bearing, stony Seteth had lost his heart to Byleth.

Dorothea couldn’t help but feel privileged to have witnessed such a sweet intimacy between the two of them, who were normally so conscientious about keeping their relationship secret (although, clearly, to no avail amongst the students in her class).

And, she had to admit, she was now curious to see what _other_ sides of Seteth she hadn’t known existed. To see him so outside of his usual behavior was… titillating, to say the least.

“I’ll bet he would be shocked to see you alone with two lovely women in your quarters,” Dorothea added, snapping the two of them from their reverie. “And at such a late hour…”

Seteth blushed furiously. “Dorothea, please,” he scolded her quietly. Though, judging by his thinly-veiled smile, he now _was_ imagining such a look on the annoying Gautier boy’s face – and rather enjoying it.

“Dorothea.” Byleth reached her hand out and softly stroked Dorothea’s flushed cheek, and Seteth and Dorothea both watched her, utterly captivated. “I would hate for you to regret this. Are you sure you haven’t had too much to drink?"

“No, not at all… I could never regret my time with you Professor…” Her voice was shaking, but her eyes were wide with desire.

Byleth smiled lightly. “That is fortuitous, because I have a great deal of love for you, Dorothea.”

Dorothea swallowed, a warmth in her chest blooming until it threatened to burn her. “Professor… I love you dearly…”

The women are locked into one another’s gaze, and Seteth can feel the heat of their proximity radiating from them. Awestruck, he can do nothing but watch with bated breath, shifting his hips uncomfortably as his body responds to the two succubus in front of him.

Turning away from Dorothea, Byleth met Seteth’s eye and held out her hand to him. “Seteth, my love, come here.”

He startles, but does as he’s told, his legs responding before his mind can even register she’s spoken. He is standing in front of them now, towering over them from their tangled position on the couch.

“Seteth, look at Dorothea’s breasts,” she said simply, as though she were requesting he hand her a quill.

His eyes shot to the floor, the deep red returning to his face tenfold. “I-I can’t!”

The women were thrown into peals of laughter, and Seteth felt his breath catch in his throat. Dorothea flashed him a huge, exaggerated frown, as though she were performing in one of her operas; it was incredibly charming. “Aww, Seteth, are you not _fond_ of my breasts?” There were false tears in her voice, and a terrifying flame in her eye. “ _Byleth_ certainly seems to enjoy them…” Byleth grinned.

“N-No, they’re lovely!” he said, his voice cracking traitorously. “I mean, from what I’ve _seen_ of them, not that I’ve seen—that is, not that I’ve _looked,_ I just… I’m _a married man!_ ” he spat out finally, flummoxed. He was floundering, completely out of his element – and the ladies seemed to relish in it.

“And _I_ am a married woman,” Byleth retorted, an infuriatingly tantalizing purr in her voice. “And yet I had _my hands_ on Dorothea’s breasts mere moments ago, and you said nothing.”

“Well, I…” Seteth paused. _I was too busy ogling your whorish ways to even_ think _of speaking,_ a long-dormant instinct inside of him whispered, and he scolded himself.

Byleth took him by the hand and gave him a gentle, sincere smile. “It is alright, Darling,” she assured him with a gentle squeeze, all joking and tipsiness gone from her now - and he was completely lost in her eyes. All of her love for him, her _desire_ for him, were so obvious in her gaze that he would likely have followed her into a fire if she’d asked. “Unless you truly do not want this?” she prods gently, providing him an out.

His heart melts, and he squeezes his wife’s hand in return. “I want whatever _you_ want, my love,” he answered. The way he looked at her then, with such adoration, such devotion, was so incredibly intimate that Dorothea couldn’t help but blush and look away.

“Then look,” she says again, and takes Dorothea’s large breasts in both of her hands roughly, eliciting a shuddering gasp from the flustered brunette. “Professor…” Dorothea sighed, gently thrusting her chest into Byleth’s embrace.

Seteth was blatantly staring now, his cock stiffening more insistently.

The sight before him was unfathomably tempting, but the basest of Seteth’s sensibilities were still nagging at him. Could he really _share_ Byleth with someone else, even if only for a while? Mere hours ago, even the thought of it would have infuriated him beyond belief – and yet…

It was Dorothea. 

Dorothea, Byleth’s closest friend. Dorothea, who had been willing to risk her life for the sake of Byleth’s multiple times. The woman that Byleth connected with the most – as a peer, as a friend, as a confidante. Dorothea, the woman who could chip away at Byleth’s placid exterior and make her _laugh_ in a way that no one else seemed capable.

 _The woman that might have_ married _Byleth, were it not for you,_ a tiny jealous voice inside him whined, but he dismissed the thought. He was certain of Byleth’s love for him, and knew in his heart that he had nothing to worry about in that regard. Even so, in spite of himself, he had always felt a fleeting dash of jealousy at the obvious bond the two women shared – a bond that perhaps _only_ two women could share.

But most importantly, there was an absolute truth that Seteth could not ignore: Dorothea loved Byleth. And anyone who loved Byleth had Seteth’s undivided loyalty. Perhaps, given the circumstances, he could allow—

“S-Seteth,” Dorothea interrupted his thoughts, her voice husky with lust. He looked at her, and found himself perturbed – and fascinated – by her green, wide, desirous gaze. “I would very much like to touch your wife’s breasts. Is that alright?” she asked politely, her eyes shining.

**Notes for the Chapter:**

> Chapter 3 is literally just sex, the whole thing is sex.


	3. Chapter 3

**Summary for the Chapter:**

> Three's company, too.
> 
> Seteth receives his orders, and happily follows through.

**Notes for the Chapter:**

> Hi, it's literally almost 4k words of just sex. I am DEPRAVED but these three give me life.   
> Fun drinking game (if you don't mind whiskey dick): Take a shot every time someone cums.

“S-Seteth,” Dorothea interrupted his thoughts, her voice husky with lust. He looked at her, and found himself perturbed – and fascinated – by her green, wide, desirous gaze. “I would very much like to touch your wife’s breasts. Is that alright?” she asked politely, her eyes shining.

His features softened a bit; he was truly touched that she was kind enough to ask him. “That… that would be fine…” he answered, his voice barely more than a whisper.

At that, Dorothea took both of Byleth’s breasts in her hands, feeling the weight of them against her palms and letting out an appreciative sigh. A bright blush overtook Byleth’s cheeks – a rare, adorable sight that wrought a quiet gasp from Seteth – and soon Dorothea closed the distance between them.

The kiss was tentative at first, as though they were unsure how to proceed. Feeling a little bolder, Byleth brought one hand up to caress Dorothea’s face, her other hand holding steadfastly to her breast. As though ignited from a spark, Dorothea used this gesture to pull Byleth closer into her and deepen their kiss. Byleth let out a soft sigh as Dorothea’s tongue caressed her own, and suddenly they were tearing at each other’s clothes, tumbling clumsily to the floor.

Mere seconds later, the two of them were naked, staring wide-eyed at the other’s nude form. Dorothea’s breasts were a unique shape - smaller than Byleth’s, with plump, dark nipples that were hardening to full attention at their newfound exposure. Byleth’s hands were on them immediately, lightly flicking them back and forth with her thumbs. Dorothea whimpered at this, and began to reach for Byleth’s womanhood.

Byleth’s eyes fluttered shut as Dorothea found her slick center, her fingers exploring her professor in gentle circles. “Dorothea…” Byleth moaned, her small pink mouth connecting with one of Dorothea’s nipples hungrily. Dorothea grinned, pleased at eliciting such a response from her professor, before Byleth slipped her hand down between Dorothea’s legs, and it was her turn to moan.

Seteth was in complete and utter awe as he watched the women touch each other. In all the centuries that passed him, and all the places he’d traveled, he had never seen something so completely, _achingly…_ _erotic_. Every explicit drawing or sinful novel he’d ever seen, every depraved imagining that had plagued him before he confessed his love to Byleth – they were nothing compared to watching her now, consumed with desire for another woman.

And, _Goddess_ , their bodies complemented one another perfectly as they pressed flush against each other, their womanly curves fitting together as if by design. The two of them were beginning to whimper, neither of them willing to stop their teasing.

He found himself leaning against the couch now, his head growing dizzy at the vision before him. The way their bodies were bouncing against each other as they urged themselves closer and closer… it was almost more than the poor saint could stand. As he watched, transfixed, his hand slipped beneath the waistband of his pants to relieve some of the growing pressure.

Suddenly, Byleth pulled away and took Dorothea’s hands in her own. Dorothea let out a small whine at the loss of Byleth’s touch, but followed her lead as her professor pulled the two of them to their feet.

“Seteth, come and touch us,” Byleth invited. Seteth, suddenly aware not only of their watchful eyes on him but also that he was now _touching himself_ in front of them, hurriedly crossed his arms against his chest and cleared his throat, averting his gaze. Despite his obvious arousal, he found himself completely incapable of moving an inch, completely at a loss for how to proceed.

Byleth, gently encouraging him, took one of his hands and placed them on her own breast. As his skin met hers, he released a breath he hadn’t realized he’d been holding, and his tense muscles visibly eased a bit. Feeling a bit more confident now, he began to trace this thumb over his wife’s nipple just as he knew she liked it, secretly relishing the way it made her eyes flutter shut.

Without breaking their contact, Byleth reached for Seteth’s other hand – and placed it gently but firmly on Dorothea’s breast. Dorothea’s breath caught in her throat.

For a split second, Seteth halted, staring wide-eyed at Byleth, then Dorothea, and back to Byleth. Dorothea’s flesh was hot and unfamiliar, her nipple naturally coming to rest in the crux between two of his fingers. The juxtaposition of their bodies was fascinating – so different, and yet so similar, so soft, so _feminine._ And yet, to be touching another woman like this – _both_ of them like this – was filling him with a perturbing mixture of shame and desire, deep in his gut.

Desperate for his touch, a whimpering Dorothea brought her hand down to her own sex and pushed herself further into Seteth’s palm. Finally, he gave her a gentle squeeze, which earned him a breathy moan – and a satisfied grin from Byleth.

His confidence building, Seteth felt himself melt into their intimacy, his fingers naturally finding a rhythm against the women’s breasts, until they were all moving together. His cock was throbbing painfully now, but he couldn’t bring himself to tear his hands away from them. The little moans and sighs they were making, that _he_ was eliciting from them, were too intoxicating to jeopardize.

“Yes,” Byleth whispered, thoroughly enjoying watching Seteth’s slowly deteriorating self-control and slipping two fingers into her own heat. “Just like that…”

Seteth’s hips rutted into the air involuntarily, his body desperately seeking relief for his aching member. Had he realized that he’d done such a thing, he would likely have broken out in a fierce blush – but instead he was completely unaware of anything besides---- _ahh!!_

A sharp hiss escaped through Seteth’s teeth as Byleth took Dorothea’s hand and placed it directly onto his cock. Byleth felt a wave of fire ripple through her as she watched her husband’s eyes darting to his groin, where Dorothea’s fingers were now wrapped around the tent of his pants.

She gave him a gentle squeeze, and Seteth squeaked. He _squeaked_. Byleth keened as her first orgasm hit her, her vision going hazy for a moment. “ _Oh, Goddess…_ ” she mouthed, unable to form the full words.

Seteth felt heat rushing from his neck to his ears, his hands slowly lowering from their breasts. To have another woman’s hand on his most intimate place like this… it felt so wrong, and yet he wanted so desperately to continue, every fiber in his being screaming at him to _mate_ , to _make them his_ , to _fuck them until they screamed his name_ —

“What a fantastic prick you have, Seteth,” Dorothea hummed, beginning to rub him up gently and down. “Such a cruel irony, for a holy man...”

Seteth, in spite of himself, felt a boyish swell of pride at her words. His mind, unfortunately, was entirely incapable of forming anything resembling a cohesive thought.

“Take them off,” Byleth demanded Dorothea, her ravenous gaze never leaving Seteth’s obscenely hard cock. Before Seteth could even process what she said, Dorothea had tugged the waistband of his pants down with one swift movement, revealing his straining, bobbing erection.

Dorothea took a moment to thoroughly enjoy the newfound spectacle before her. Though she was certainly no stranger to the male form, it had been quite a while since she had allowed any of her many suitors to reach this level of intimacy with her. And something about it being _Seteth_ , the Church’s normally repressed, devout second-in-command, was making her cunt ache to be filled.

“Green, as well,” Dorothea chirped, bringing her hand down to the root of him and marveling at the soft, thick curls she found there. Byleth giggled at that, coming down from her first blissful release but never taking her hand away from her center.

“Play with it as much as you want,” Byleth purred in a sultry voice, backing away just a bit to get a better view. She had never felt desire of this caliber – the two people she loved most in the world, naked and wanting in front of her. “But, careful not to make him come. We need him ready and willing.”

Dorothea nodded, and lowered herself to her knees, watching with delight as Byleth played with herself at the sight of them. She brought both of her hands to him now, one stroking up the length of him while the other gently caressed his bullocks. A thin layer of clear liquid pooled at his tip, and she swirled it around with her thumb, causing him to shudder.

Seteth watched in wide-eyed wonder as Dorothea studiously touched him with expertly skilled hands, sending waves of pleasure through him and causing him to moan. He glanced over at Byleth, who was staring at him intently, an extreme hunger in her eyes; under different circumstances (particularly when she was angry with him), such a look might have sent a shiver down his spine, but now it only made him ache to capture her lips with his.

Ah, but Dorothea’s hands felt incredible… so good, so _wrong_. She was undeniably beautiful, even more so now that her eyes were filled with lust and her perky tits peeked through the curly ends of her wavy brown curls. She was also incredibly _curious_. Every move she made was slow and deliberate, taking her time to discover which movements made him sigh, shiver, moan…

The aching pressure inside of him was building as she became more daring, slowly learning exactly what felt good. “You are… very good at this, Dorothea,” he choked out, his voice cracking at the first words he’d said in what felt like years. His eyes widened as he realized the implications of his words, hoping he hadn’t offended her - but Dorothea simply laughed and thanked him, obviously endeared by his awkwardness.

Goddess, she was stroking him faster now…

“Your mouth,” Byleth demanded, her voice husky and strained. Through half-lidded eyes, she watched as Dorothea opened her mouth wide and engulfed him. Seteth gasped, his eyes screwing shut at the overwhelming new sensation.

“Mmmmm,” Dorothea hummed around his length, caressing him with her tongue.

Byleth cried out now, her voice reaching a higher volume than Dorothea had ever heard it, as another orgasm crashed over her. Seteth watched in awe as she thrust her hips against her own hands, the perfect image of a wicked siren calling him to his death…

He was close—far too close. Seeing his wife in the throes of ecstasy, along with feeling Dorothea’s talented mouth on his manhood, was forcing him dangerously close to the edge. _Oh, but he needed it so badly_ …

“S-Stop…” Seteth mumbled, his voice hardly audible even to his own ears. Unsurprisingly, Dorothea hadn’t heard him. Beginning to panic, Seteth grabbed the sides of her head, perhaps a little rougher than he intended, and pulled her off of him with a pop – and not a second too soon. “ _Stop!_ ”

He looked down at her now, with her hair tousled between his fingers and a devilish grin on her face. “I… I’m sorry,” he said gently, “I didn’t mean to be rough, but I – I almost…”

Byleth stood. “Enough,” she silenced him, her voice thick and gravely as she swept Dorothea into her arms. “Mine now,” she breathed as she all but tackles Dorothea to the ground, bringing her knee to press against Dorothea’s hot, twitching folds.

“ _Please_ , Professor,” Dorothea begged with a whine, her head lolling to the side as Byleth’s leg gyrated against her. She wanted, she _needed_ so badly for her professor to make her… “M-more!”

With that, Byleth grabs Dorothea’s knees and yanks them apart. “Shhh, good girl,” Byleth soothes, positioning herself so that their cunts are mere inches apart, their legs tangling around the other’s body. “I’ll take care of you.”

With that, Byleth thrust herself against Dorothea with a satisfying wet _smack_ , and Seteth watched as Dorothea tossed her head back with a high-pitched cry. 

It took no time at all for them to find their rhythm, grinding their needy centers against one another until their clits met, and both women began to groan.

“Yes… yes… yes.. yes…” Dorothea keened with each thrust, her heavily lidded eyes seeing nothing as she chased her release, closer, closer…

Seteth’s hand darted to his cock and began pumping it furiously, his eyes never leaving them for a second. There was something so enchanting, so mesmerizing, so undeniably _female_ about their bodies, rocking and rolling against one another like waves of a stormy sea. 

With a choked sob, Dorothea shook wildly against Byleth’s center, every muscle in her toned body clenching as she crashed over the edge. “Professor!” she screamed, and fell to the ground with a thud as her exhausted muscles gave out.

But Byleth wasn’t finished with her yet.

“Seteth.” She called to him sternly, with the authoritative tone she used to command battalions; it made his cock twitch. He removed his hand from himself with a whine. He couldn’t remember ever needing release so badly. “You are in charge of Dorothea’s breasts,” Byleth finished, and dove between Dorothea’s legs.

Byleth kissed Dorothea’s dripping lips, filling her nose with their combined scent, then began to explore her with her tongue. Dorothea, still weak from her first orgasm, wriggled against Byleth’s face with a rather adorable whimper. Byleth traced her tongue teasingly around the small bundle of nerves at the crux of her sex, frustrating Dorothea to no end.

Meanwhile, Seteth brought himself to his knees and positioned himself above Dorothea’s head, his hands claiming her breasts greedily now. _“Yes,”_ Dorothea sighed, arching her back so as to grant Seteth better access. He indulged himself for a moment, squeezing and flicking her nipples sporadically for his own enjoyment, before matching the rhythm of Byleth’s tongue as best he could.

Dorothea couldn’t believe how close she was again. Between Seteth torturously teasing her sensitive nipples, to Byleth _finally_ finding her nub with the tip of her tongue and flicking it mercilessly, she couldn’t possibly take much more…

But then, Seteth covers her nipple with his mouth, his tongue swirling over it again and again in perfect time with his fingers and Byleth’s tongue on her heat – and she completely comes undone. “Yes! Oh, _fuck_!” she cries, feeling her muscles clench madly around Byleth’s face.

For several moments, Dorothea is unable to move, panting so hard that her tits are wobbling in opposite directions. Then, propping herself up on her elbows, she slips her fingers between Byleth’s legs.

Byleth, thrilled at the attention, spreads her legs wide for her and locks eyes with her husband. “Come here,” she whispered, grabbing one of her breasts and presenting it like an offering.

Starving for her, Seteth does as he’s told and immediately his mouth is on her. With a grin, Byleth grabs the back of Dorothea’s head and slowly pulls her to the other breast, while using her own free hand to stroke her husband’s desperate, leaking cock.

And so they are all intertwined – Byleth, with a lover suckling madly at each breast, tugging at Seteth’s prick while Dorothea’s fingers fill her…

Seteth, having finally used up his last ounce of restraint, can hold back no longer, spilling himself into Byleth’s hand as he groans against her tit. This pushes Byleth over the edge again as well, and she can feel herself contracting around Dorothea’s slim fingers, completely enthralled by the sight of the two of them on her breasts.

Dorothea pulls away now, grinning proudly at Byleth’s frazzled appearance. Seteth can hardly breathe, unable to do so much as blink as he recovers from his climax.

“Now, Seteth,” Byleth huffs, after taking a moment to regain control of herself. “Fuck Dorothea.”

Seteth’s jaw drops. Surely he couldn’t have heard her correctly…

“But… Darling, I just--” His eyes trailed down to the sticky mess of his seed covering his wife’s thighs, his cheeks reddening a bit at the sheer amount of it.

“And yet…” Byleth said, using her finger to poke playfully at Seteth’s cock. It was, indeed, still rock hard; Seteth was rather astonished, himself.

Dorothea giggled. “Quite a trooper you’ve got there, Seteth.” He felt his blush grow deeper.

“I know you want to,” Byleth added, her voice adopting an _obscenely_ alluring lilt as a grin spread across her face. “So fuck her.”

Seteth blinks, a hurricane of conflicting thoughts racing through his head. This had been… surprisingly enjoyable, to be sure, but to actually be _inside_ another woman?

“I… I-I…” he stutters, scrambling for words, until Byleth brings her hand up to his cheek tenderly.

“It is fine, Seteth,” she reassures him with a calm murmur, eyes twinkling. “I _want_ you to. I want to _see_ you, the two of you… together.”

She can see by the look in his eyes that she is getting through to him - his primal instincts are working in her favor. There is still a hint of hesitance there, however, so she pulls him in to her and plants a long, sweet kiss on his lips. The kiss is loving, sincere – and in an instant, Seteth can feel the last of his reservations drifting away.

Byleth pulls away, a slightly smug glint in her eye as she recognizes her victory.

“Now, then. As your Archbishop, I _order_ you to fuck Dorothea.”

And so he does. He is nervous at first, unsure how to take the lead, so Dorothea wraps her hands around his cock. “I want you inside me,” she whispers, her lips mere inches away from his ear. Seteth feels a shiver of electricity shoot to his groin, hearing such lewd temptations from someone besides his wife. His hips begin to rock back and forth with her fingers, his body naturally taking over for his exhausted mind.

“Please,” Dorothea whimpers, flashing Seteth a well-practiced look that she knew drove men wild – the pleading look of a diva, addled with lust, searching for someone to make her complete.

Seteth was no exception, it seemed, as he moved to hover over her, aligning himself with her entrance.

Byleth watched, utterly hypnotized, her fingers finding their way to her folds again.

Their coupling is clumsy at first – slow, awkward, groping. Dorothea’s body is different from Byleth’s, of course, and before Byleth came along Seteth hadn’t been with a woman in… well, _centuries_. He is a bit too hesitant at first, careful not to hurt her, but Dorothea soon puts those fears to rest.

“ _Fuck,_ Seteth,” Dorothea hisses, grabbing him by the ass and pushing him deeper inside of her, all the way to the hilt. He lets out a guttural moan and clenches his fists around her thighs, steadying himself. “Yes.”

Encouraged, he begins thrusting into her, his mind swimming at the unfamiliar sensation of another woman’s cunt hot and slick around him. Dorothea slid one of his hands from its place on her thigh up to her breast, and gave both their hands a squeeze. Following her example, Seteth began to flick at her pert nipples, allowing both hands to explore her body.

They are moving at a steady pace now, growing ever more confident as they adapt to each other’s bodies. Dorothea begins to keen with each of his thrusts, the head of his cock hitting her most sensitive spot with every sway of his hips, and Seteth begins to thrust a little harder…

“How does it feel to be inside her cunt, Seteth?” Byleth asks from behind them, her voice crackling with desire as she fought to be heard over Dorothea’s mewls.

Seteth felt himself twitch inside Dorothea, unable to tear his eyes away from her breasts as she moved beneath him. Hearing such a _filthy_ word from Byleth’s mouth… while she watched him fuck someone else, no less…

It was driving him absolutely wild.  
  


“It feels… amazing…” Seteth admits, his voice barely more than a whisper.

“WHAT feels amazing, Seteth?” Byleth demands, and Seteth has to bite his cheek to keep himself from getting carried away.

“Her…” Seteth felt a mad flush of shame spread across his cheeks, unable to bring himself to say it. “Her c-..”

“Say it!” Byleth barked, even louder this time.

“ _Her cunt_!” Seteth cried out, tossing his head back in defeat as Dorothea ground her hips into him, urging him closer still. “Her cunt feels amazing!”

Dorothea and Byleth both moaned at Seteth’s language, and Dorothea pulled herself off of him just long enough to flip herself over onto her hands and knees. Seteth wasted no time in shoving himself back inside, sending a shockwave of pleasure to Dorothea’s core.

“What do you think of my husband’s cock inside you?” Byleth asked, allowing herself to come forward a few inches to get a closer look.

“S-s-sooo…. So good!” Dorothea whined, her frantic voice betraying how close she was to reaching her peak. “H-Harder! Seteth, please, ohhhh--”

Seteth felt Dorothea clench violently around him, a piercing cry filling the room as she came. Her climax was earth-shattering, and for a long moment she could see nothing but stars as her body spasmed.

Seteth pulled out as swiftly as he could, barely holding on by a thread. “Darling, please!” he yelped, holding his hand out to Byleth like a drowning man. “I’m so close! I want you!”

Byleth, happy to oblige, crashed her lips against her husband’s as his hands found their usual spot on her hips, pulling her on top of his cock with a desperate groan.

She felt perfect.

Dorothea, slowly returning to reality, watched as Byleth rode Seteth, their movements perfectly in sync like a well-rehearsed dance. Seteth lasted merely seconds before releasing into his wife with a fervent yell she had only ever heard from him on the battlefield. Byleth, bouncing on top of him, followed right behind him.

Dorothea felt her heart swell for her professors; they really were a perfect pair.

For a long while, no one could say anything. The room was silent now, except for their panting breath as they recovered; utterly, completely satiated, spent, exhausted.

There is a brief moment of slow dread as Seteth begins to wonder if they’ve made a mistake – if things will be difficult between them now.

“Well!” Dorothea squeaked, bringing herself to her feet and gathering her clothes. “I certainly enjoyed our after-hours book club meeting!”

The three of them broke into comfortable laughter, and Seteth’s mind was at ease.

Byleth gave her friend a mirthful smile. “Goodnight, D.”

“Goodnight, Professor. Seteth.”

Dorothea gave a small wave and headed for the door, leaving Byleth to wrap her poor husband’s tired arms around her as she led him to their bed.


End file.
